Table 23 



Los Angeles and Long Beach Breakwaters 



Los Angeles and Long Beach Harbors, California 



Date(s) Construction and Rehabilitation History 



1898- Construction of the 1 1 , 152-ft-long San Pedro Breakwater occurred at 

 1910 the site (Figure 29). The harbor side of the structure was built 



with 1V:1.2H side slopes, while the ocean side consisted of 1V:1.2H 

 slopes from the bottom up to an el of -12 ft mllw. At this point 

 the slope changed to 1V:3H to an el of 0.0 ft mllw. The rubble- 

 mound portion of the structure (Figure 30) was 47 ft wide at el 

 0.0 ft mllw. Granite blocks (up to 20 ton) were laid in courses to 

 an el of +14 ft with a crest width of 20 ft. The rubble-mound 

 portion of the structure was constructed with 8- to 10-ton stone 

 and was permeable. Other structures, which are now incorporated 

 into the inner harbor works, were constructed as early as 1871. 



1930- Construction of the 18,500-ft-long rubble-mound middle breakwater 

 1938 (Figure 29) was in progress. The breakwater had a 16-ft crest width 

 at el +14 ft mllw. Side slopes on the ocean side were 1V:2H and on 

 the harbor side ranged from 1V:1.25H to 1V:1.5H (Figure 30). An 

 impermeable core was installed from the bottom (approximately 

 -50 ft mllw) to el -26 ft mllw. 



1942- Construction of the 13,350-ft-long rubble-mound Long Beach Break- 

 1960 water (Figure 29) occurred during this period. With the exception 

 of the breakwater core el (Figure 30) the cross section of this 

 structure was similar to that of the middle breakwater. 



1947 Repairs to the middle breakwater were accomplished for a cost of 

 $786,700. 



1983 Winter storms resulted in extensive damage to the San Pedro Break- 

 water. The structure was breached in an area immediately seaward 

 of the curved portion of the breakwater. Model tests were con- 

 ducted after the damage (Carver 1984, Baumgartner, et al. 1986), 

 and restoration of the San Pedro Breakwater was subsequently 

 completed. Work consisted of the placement of approximately 

 25,000 tons of salvage stone and new angular stones ranging from 

 15 to 25 tons each. Where voids occurred on the crest after this 

 stone placement, concrete was pumped into flexible temporary forms 

 to complete the repair. 



1986 The breakwaters presently are in good condition. 



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